This invention relates to the passivation of metals on a cracking catalyst and, more particularly, is directed towards a novel process for enhancing catalytic performance by an improved process for prevention of the detrimental effects of metals, such as nickel, vanadium, and iron on the activity of a cracking catalyst when the same is used in a cracking process having essentially no hydrogen added thereto and wherein the cracking catalyst has been treated with antimony metal or a compound of antimony prior to subjecting the cracking catalyst to hydrocarbon cracking conditions.